How big a difference does the bike make?

2 things I've noticed are behind this question: 1. In the Giro today (no spoilers here) Paul was talking about how the avg.speed might break the record which has held since 1983. Now I'm probably more familiar with state of the art from 83 than I am today. A TdF bike then weighed 20.5-21.5 pounds a good 4 pounds more than current.
#2 is the every now and then thread about someone showing up for a ride on an, let's say, "inappropriate" bike but still keeping up; apparently to the amazement of all.

Obviously the engine is of supreme importance and human beings haven't changed in 20 years so how big of an advantage is the bike? Noone doubts that a time-travelling Eddy Merckx could compete in today's peloton but could he do it on that Molteni Orange steel friction-shifted antique of his?
Maybe I've got too much time on my hands if I worry about things like this.

“Life is not one damned thing after another. Life is one damned thing over and over.”
Edna St. Vincent Millay

I would say it is 90% the person and 10% the bike. Let's say a bike is 5 lbs lighter now then 20 years ago, but the person weighs 140 pounds what is that 5 lbs? The bike can help a good rider perform better, but not a dramatic difference.

TREK 1000 and a junk bike with a basket on the front to go to the shops.

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5 pounds is 5 poulds less that you have do drag up a hill, or fight rolling resistance against. So it can make a difference. But the thing is so many people who aren't anywhere near the fitness level where it makes a difference spends hundreds of dollars to shave off grams at a time. That part is just silly.

Originally posted by Spire 5 pounds is 5 poulds less that you have do drag up a hill, or fight rolling resistance against. So it can make a difference. But the thing is so many people who aren't anywhere near the fitness level where it makes a difference spends hundreds of dollars to shave off grams at a time. That part is just silly.

This has been of considerable interest to me since I started riding last year. It seems difficult to get the precise data I would like, but what specifics I have found tends to show little improvement from considerable weight changes. The example I've posted here before was about a 10 lb weight reduction only saving 33 seconds over a 20 mile course of varying terrain! Unless you are racing, that seems pretty meaningless to me, even though I am always trying to get faster. It would be hard to justify spending a lot more money only to save such a small amount.

My present theory is that most bike riders who spend a lot of money to get a lighter bike are wasting their money (but yeah, I'll will get a lighter one myself in a couple years). They will make far more improvement as they get in shape and develop skills.

But I still wonder about how much difference a lighter bike can make. I'd like to see comparisons of acceleration from 0 to certain speeds (ranging from 15 to 20 mainly) because I have lots of stops on my runs - I know it can be as high as 20.

I'd also like some comparisons on hills of specific inclines (and descents since heavy bikes are supposed to be better at that).

One thing I like about a lighter bike (this one is lighter than my first) is that it is easier to lift up onto the bus bike rack!

My own view is that it's not worth it to spend a lot of money for weight reductions unless you're a serious racer. Let's take a fairly dramatic example.

Suppose you normally produce about 250 watts on a 5% climb and go about 11mph, an ok pace. Suppose you added 2kg to your bike, about 4.5lbs, and made no other changes. How much time would you lose?

Well, what your lighter self would ride in an hour of relentless climbing at 5% your heavier self would do in 1hr 1 min 10 sec. So the 4.5 lbs would cost you one minute ten seconds over 11 miles of continuous 5% climbing.

How much money is it worth to you to get rid of this weight?

Keep in mind, too, that we're talking about the difference that 4lbs of additional weight makes, and not the tens of grams one usually deals with in dropping weight from a decent road bike. If you've got a decent middle range bike-- a Trek 1200 or something-- it would cost several thousand bucks to upgrade to a bike 4lbs lighter. Is that worth it?

Also remember that if you're a faster rider to begin with, the time gains from less weight are even less.

You shouldn't forget, either, that typical rides with clubs or even in local races aren't up continual climbs, so the time cost on typical club rides would be much less than that minute-ten. And of course there are all of the other factors that tend to keep clubs together on the road, even with significant variation in bikes and riders.

Now a little time means a lot in a race. But for my money, if you're not racing seriously the weight reductions aren't worth the jump from middle- to high-end bikes. Of course, there are other benefits to higher end bikes, better gruppo, better style, maybe more durability, whatever. If those things are worth it to you, that's another topic. But the weight benefits are overestimated by many riders, I think.

One other thing that's worth mentioning are the common comparisions among realizing time gains by losing weight on the bike or on the person or by gaining strength. Even some people above say it's cheaper to lose weight on your body than on your bike, for example. This is true, but it isn't the relevant comparison. Even if you decided to put a lot of effort into losing weight on your body or in getting stronger there's no reason you couldn't make your bike lighter also. So the real question is whether the money is worth the time improvement from bike weight loss, whatever else you decide to do to go faster.

I doubt there is many exact comparisons like that.. WHen you shave weight off a bike, there area ALOT of factors involved. Material a frame is made off, could make it stiffer so better power transfer, more aerodynamic wheels.. etc.. so direct comparison in speed difference would be hard to do.

you can never place too much emphysis on comfort. Most of us have started out on heavy cro-mo and advanced to aluminum for its lightness and stiffness. then many gravitate towards lighter steel of today for comfort-sake. up the food chain is the titanium and the carbon fiber models.

I have been embarrassed out there by bike messangers on beat-up raleigh's wearing jeans and other street attire. He had 6 gears in the back and an older wheelset, but he glided along quickly and efficiently.

Which brings us back to the 'when all else is equal' part. In racing today, the training is better as well. Today they train in wind tunnels, with precise HR zones, better nutrition, better staffing (shuttles, hotels, chiropractors, nutritionists, trainers, sponsors)

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RC try link above or goto analyticcycling.com and try some #'s,I think you'll find that the gains from weight savings are pretty freakin minimal,aero makes a bigger difference per $$/spent than any other improvement.More evidence can be pretty instinctive....example recumbents,streamliners>hpv's etc....some of those things are quite heavy,but for flatland speed aero is everything.Just like many think the switch from mtb to roadie is a huge automatic speed gain,it isnt........both can be set up pretty closely and you'll find the diff in rolling resistance@20mph tween a mtb and roadie is only about 15watts,barely noticable.(assuming good slicks and similar riding position) I ride a couple bikes that as bout as different as they can be weight wise,one is about 32lbs,other is around 16.5lbs,similar gearing and riding positions.....yes I can feel a difference tween the two,it might save me 5mins in a 30mile alleycat race,or save me some calories I need to eat after a workshift,but the difference isnt enough to worry about.Unless your climbing most of the time,and steep stuff...>8% or more being a weight weenie just doesnt pay well.Its easier to get more aero and or/add more power.Much more effective too....why obsess over grams when with some work you can increase your power output by 50% or more?

Hi,
nice thread, but I would like to go back to the avg speed comment. I find that amazing. Not only are the bikes lighter, bur training methods have advanced
remarkably. I would also think the lower amounts of body fat guys are carrying would also make a difference. I am going to assume for the sake of argument that we are faster; and the difference is being obscured somehow. Can anyone speak to this?

...that this nation, shall have a new birth, and that government of the corporation, by the corporation, for the corporation, shall not perish from the earth.

Yes the avg speeds have increased,training has gotten better and more aero from testing in windtunnels etc.The gains from weight savings however are prob less than 1%,but the gains from better training/bike set-up are prob around 3-5% if the tdf stats are any indication.Being the right size physically is a huge component...example,pre cancer Lance was too heavy,carried too much upperbody muscle around,post cancer he was able to achieve the current typical size range and power output of a top ten elite pro stage racer.This is still gains in performance measured in seconds over MANY miles.Could Merckx compete on a 20-30yr old bike in todays peloton.....Id guess yep,on a flat stage sure,wouldnt make much difference,hilly stage...maybe,I think the results would suprise some folks.Some of the performance gains are still gonna be masked by teamwork,strategy,course,and just plain luck.

Horndude expressed some sentiments similar to mine using the Merckx analogy. I think we make a mistake getting too analytical when looking at human performance. The website mentioned above tells me that a reduction of X grams leads to Y gain in avg speed over N miles just like it was real math. With a constant output engine I wouldn't doubt it but the human being, even in top form is very much a variable output motor.

The fact is today's riders aren't riding much if any faster than 20 years ago despite tremendous changes in bikes and perhaps training. I like that to be honest. It keeps the connection between past and present very much alive in the sport. I happen to think that Eddy M. could hop out of the time machine and, if he found a team that'd work for him, give Lance and the boys a hard time regardless of the difference in bikes. There's just so many human factors involved in racing that they'll never be all quantified.

“Life is not one damned thing after another. Life is one damned thing over and over.”
Edna St. Vincent Millay

While I am in agreement with most of the above - it is the engine, not the bike - it is difficult to compare times from one Giro to the next, even twenty years apart. Unless the Giro is run over exactly the same routes then the comparison is meaningless. Even then, it is very suspect as the road surfaces today are probably improved from 20 years ago. And I would believe that the riders of today, with a few notable exceptions, are better trained athletes than those of 20 years ago. Would be interesting to see what Merckyx (the senior) could do today with modern training. My guess is that he would still be one of those at the top of the game, but not the dominate person he was then. But we will never know.

I do disagree with those who criticize others who spend money on lighter bits for their bike. This is a free, capitalist country and we are all free to spend our money how and on what we want. Power to you if you ride a Record equipped Cielo. It's your $10,000 and you can spend it any way you want.

Now I have to go and see if I can't make my bike's engine perform a little better. The bike is as light as it is ever going to get.